#include "createRDeltaT.H"

Info<< "Reading field p_rgh\n" << endl;
volScalarField p_rgh
(
    IOobject
    (
        "p_rgh",
        runTime.timeName(),
        mesh,
        IOobject::MUST_READ,
        IOobject::AUTO_WRITE
    ),
    mesh
);

Info<< "Reading field U\n" << endl;
volVectorField U
(
    IOobject
    (
        "U",
        runTime.timeName(),
        mesh,
        IOobject::MUST_READ,
        IOobject::AUTO_WRITE
    ),
    mesh
);

#include "createPhi.H"

Info<< "Reading transportProperties\n" << endl;
immiscibleIncompressibleTwoPhaseMixture mixture(U, phi);

volScalarField& alpha1(mixture.alpha1());
volScalarField& alpha2(mixture.alpha2());

const dimensionedScalar& rho1 = mixture.rho1();
const dimensionedScalar& rho2 = mixture.rho2();


// Need to store rho for ddt(rho, U)
volScalarField rho
(
    IOobject
    (
        "rho",
        runTime.timeName(),
        mesh,
        IOobject::READ_IF_PRESENT
    ),
    alpha1*rho1 + alpha2*rho2
);
rho.oldTime();


// Mass flux
surfaceScalarField rhoPhi
(
    IOobject
    (
        "rhoPhi",
        runTime.timeName(),
        mesh,
        IOobject::NO_READ,
        IOobject::NO_WRITE
    ),
    fvc::interpolate(rho)*phi
);


// Construct incompressible turbulence model
autoPtr<incompressible::turbulenceModel> turbulence
(
    incompressible::turbulenceModel::New(U, phi, mixture)
);


#include "readGravitationalAcceleration.H"
#include "readhRef.H"
#include "gh.H"


volScalarField p
(
    IOobject
    (
        "p",
        runTime.timeName(),
        mesh,
        IOobject::NO_READ,
        IOobject::AUTO_WRITE
    ),
    p_rgh + rho*gh
);

label pRefCell = 0;
scalar pRefValue = 0.0;
setRefCell
(
    p,
    p_rgh,
    pimple.dict(),
    pRefCell,
    pRefValue
);

if (p_rgh.needReference())
{
    p += dimensionedScalar
    (
        "p",
        p.dimensions(),
        pRefValue - getRefCellValue(p, pRefCell)
    );
    p_rgh = p - rho*gh;
}

mesh.setFluxRequired(p_rgh.name());
mesh.setFluxRequired(alpha1.name());

#include "createMRF.H"
#include "createFvOptions.H"

// All fields below are used to calculate porosity effects following the names
// in Jensen et al 2014.
// Currently the fields must be in the 0 directory.
// They are not written again so restart is not possible.
// Fields could instead be defined as zones if they are all constants.
// This would save memory and disc space.
// However, we would not be able to define a smoothly varying porosity field.

volScalarField porosity
(
    IOobject
    ( 
        "porosity",
        runTime.timeName(),
        mesh,
        IOobject::MUST_READ,
        IOobject::NO_WRITE
    ),
    mesh
);

volScalarField alpha
(
    IOobject
    ( 
        "alpha",
        runTime.timeName(),
        mesh,
        IOobject::MUST_READ,
        IOobject::NO_WRITE
    ),
    mesh
);

volScalarField beta
(
    IOobject
    ( 
        "beta",
        runTime.timeName(),
        mesh,
        IOobject::MUST_READ,
        IOobject::NO_WRITE
    ),
    mesh
);

volScalarField gamma_p
(
    IOobject
    ( 
        "gamma_p",
        runTime.timeName(),
        mesh,
        IOobject::MUST_READ,
        IOobject::NO_WRITE
    ),
    mesh
);

volScalarField d50
(
    IOobject
    ( 
        "d50",
        runTime.timeName(),
        mesh,
        IOobject::MUST_READ,
        IOobject::NO_WRITE
    ),
    mesh
);

volScalarField KC
(
    IOobject
    ( 
        "KC",
        runTime.timeName(),
        mesh,
        IOobject::MUST_READ,
        IOobject::NO_WRITE
    ),
    mesh
);

// Interpolate porosity field onto faces used in convective term
surfaceScalarField porosityF = fvc::interpolate(porosity); 

// Interface advection constructor modified to take the porosity  
isoAdvection advector(alpha1, phi, U, porosity);
